Add Table on the generated Column enum

[Sytten]

This might seem weird, but it comes from a legit need to no change hundreds of lines of sea-query code.
Currently we have a lot of enums like:

#[derive(Iden, Clone)]
pub enum InterceptEntries {
    Table,
    Id,
    RequestId,
}

That we use like:

Query::select()
.column((InterceptEntries::Table, InterceptEntries::Id))
.column((InterceptEntries::Table, InterceptEntries::RequestId))
.from(InterceptEntries::Table)
// Wayyyy more code 

We want to use sea-orm for all the most simple use cases, but doing so would imply having to change all the InterceptEntries::Table to intercept_entries::Entity and InterceptEntries::Id to intercept_entries::Column::Id.
That is a lot of code for us.

A smoother transition would be to just change the import:

use entities::intercept_entries::Column as InterceptEntries;

But it would require the Column enum to have a Table field.

Maybe this could be a flag only for people that need it?

[billy1624]

As discussed on Discord. It's doable and we should implement it :P

[tyt2y3]

Great, and thanks for the PR

[tyt2y3]

0.4.2